US mandates vaccines or tests for big companies by Jan. 4

In this Sept. 14 file photo, a syringe is prepared with the Pfizer COVID-19 vaccine at a clinic at the Reading Area Community College in Reading, Pa. (AP Photo/Matt Rourke, File)

Tens of millions of Americans who work at companies with 100 or more employees will need to be fully vaccinated against COVID-19 by Jan. 4 or get tested for the virus weekly under government rules issued Thursday.